Erythromycin is a macrolide that inhibits protein synthesis by binding to the 50s subunit and prevents peptide translocation from site A to P on the ribosomal subunit. It is a 14 membered lactone that contains two sugars. It is widely absorbed and distributed except in the brain and CSF. It is hepatically eliminated and is also an inhibitor and a substrate of of CYP 3A4. Further it is unstable in acid and its structure has to be modified including being enterically coated to reduce hydrolysis at the C9 ketone and C6 OH . It is available in different forms including A,B,C,D,E and F although the A form is the most effective against bacteria. It is generally most active against aerobic gram positive bacteria. …show more content…
It inhibits the synthesis of DNA by binding to dihydropteroate synthase thus preventing the synthesis of thymidine (dTMP). It is orally absorbed and widely distributed in all tissues including the CNS, CSF and even into a fetus. The benzene ring is required for the activity of this drug. The nitrogen on the sulfonamide group is monosubstituted to increase activity and the amino group on the benzene ring is unsubstituted. It undergoes phase II metabolism via aniline glucuronidation and sulfonamide acetylation and is renally eliminated. Some of its adverse effects include sulfa allergies and is cross allergic to other sulfa containing